


Irresistible

by leonard_mccoy



Category: The Infernal Devices Series - Cassandra Clare
Genre: Bisexual Sebastian Morgenstern, Bisexual Will Herondale, Canon Divergence, Gay Jem Carstairs, M/M, Mentions of addiction, The infernal devices au, completely consensual but Jem doesn't know everything Sebastian can do, it's mainly just really gay
Language: English
Status: Completed
Published: 2018-12-22
Updated: 2018-12-22
Packaged: 2019-09-24 18:44:08
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 871
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17106098
Author URL: https://archiveofourown.org/users/leonard_mccoy/pseuds/leonard_mccoy
Summary: In the depths of the London Institute, 1867, Sebastian Morgenstern finds himself intrigued by a dying James Carstairs.





	Irresistible

“Why me ?” Jem asked for possibly the millionth time that hour as he watched the taller Shadowhunter examine his reflection in the mirror. 

“Because you, James Carstairs, harbour the sort of addiction that truly intrigues me.”

Sebastian turned around, smiling slowly, eying the silver-haired Shadowhunter leaning against his headboard. The two of them would be undisturbed in this corner of the Institute, that was for sure, but Sebastian didn't quite care if any of the usual inhabitants found them. Jem was quite willing for this to happen, despite his wariness. 

“I intrigue you because a demon injected me with a deadly powder that will cause my untimely demise?”

“No. You intrigue me because you've survived.”

“Sebastian, I am a dead man walking.”

Jem let out a shuddering breath as the other boy lightly traced his sharp collarbone. 

“I know. And it's fascinating.”

“Sebastian, please.”

“How does it feel, James?” Sebastian asked softly. He'd crept an inch closer now, laying himself over the other boy.

“How does what feel?” Jem met his eyes curiously. He didn't ask why both were black, nor did he inquire about the demonic energy Sébastian was radiating. 

“Me. How do I feel, do you feel when I have you like this?”

“I feel…your power.” Jem didn't flinch when Sébastian's lips connected with the side of his neck. “And your….energy..”

“The demon blood within me is surging to connect with the drug within you” Sébastian murmured, licking a stripe up Jem's neck. “And all you have to do….is allow it.”

Jem shivered, parting his legs slightly. 

“I am not exactly shying away from this.”

“No but you have to want it.”

Sébastian's dark eyes gleamed with a carnal hunger. 

“I want you to say it.”

Jem met his gaze slowly. 

“I want you, Sébastian Morgenstern.”

The taller Shadowhunter was on him with surprising agility, pinning his wrists above him with one hand, working to unbuckle his trousers with the other. 

Jem did not move as he watched him, each movement antagonisingly slow, as though meant to take him apart with nothing but sheer cruelty. Jem had not been with another man since Will, but Will had been desperate, eager, unable to wait. Sebastian was completely different. He was fire itself, a burning, scorching flame with a mind of its own, and Jem could not read him. 

 _If Will could see me now_ he thought, but the thought lasted for only a second more, before he felt sharp pain and pure pleasure collide. 

“You know, it's usually polite to look into the eyes of the person inside you when they actually are inside you” Sébastian told him with a wicked smile, and Jem bit back a moan. He had barely felt anything before Sébastian had entered his body, which explained why the process had suddenly seemed to have been accelerated. 

“Politeness is deception” Jem replied through gritted teeth. “However I will do whatever pleases you the most.”

Sebastian chuckled darkly. 

“Flattery, James, will get you nowhere.”

“I thought there was no rush.”

“There is now.”

Jem felt the grip on his wrists tighten as Sébastian started to move, ever so slowly, not breaking his gaze. 

Jem's eyes were beautiful he thought. All that silver could be moonlight on the water, and yet here it was, the mirrors of the soul lying beneath him, the doorways into a dying mind. 

Doorways that none but himself would enter, of that he had made sure. Jem was his, and this caused more power to surge through their bodies as Sébastian quickened his pace. He was careful, knowing the fragility of Jem's bones, but not too careful, as after all, he did want him to feel. He wanted him to feel the burn, the sting, the flame, the darkness. Sebastian wanted him to feel everything. 

Jem only shivered, arching his back with each thrust, his lips parted halfway. He was indeed on the edge of falling apart, but his conscious mind was telling him to hold back. To wait. Sebastian was not Will. Will would force both of them over the edge as soon as he could. Sebastian appeared a lot more calculated, and the last thing Jem wanted was to displease him. 

Sébastian smirked deeply, fully aware of Jem's thoughts. What the other boy was not aware of was the sheer amount of power the Morgenstern truly had. With a few simple words, Jem's mind was his own, a thought that caused him to increase his pace further as he tightened the grip on Jem's fragile wrists. He has given me so much Sébastian thought, groaning with the effort of keeping his thrusts steady. But does he know how much I can give him?

“Sebastian” Jem was choking out, shaking with the effort of holding back. 

Sébastian's lips twitched into a feral smile as he traced the pulsing veins in Jem's neck.

“Come for me, James” he whispered, pressing down harder, wanting to feel Jem's heartbeat accelerate with the force of his orgasm. 

And Jem came, fainting from the raw power that surged through him. 

Sébastian's eyes gleamed as he watched the other boy fall apart. 

“Mine” He hissed, coming inside him. 

Jem was too far gone to hear. 

 

 


End file.
